Quantum yields of charge carrier formation, ϕ; (cc), in poly(biphenylmethyl silylene), PBMSi, and poly(methylphenyl silylene), PMPSi, have been determined at 23 °C with the aid of the xerographic discharge method. At F = 1 × 108 V/m and λinc = 330–360 nm: ϕ (cc) = 0.10 (PBMSi) and ϕ (cc) = 0.03 (PMPSi). Upon the addition of 2,3,5,6-tetrachlorobenzoquinone (chloranil) at c = 3 mol%, to the polysilylene films, the quantum yields were increased: ϕ (cc) = 0.21 (PBMSi) and ϕ (cc) = 0.13 (PMPSi). The mobility of charge carriers μ in PBMSi is about one order of magnitude lower than in PMPSi. Upon addition of 3 mol% chloranil to PBMSi μ increased slightly.